System safety defined

PRESSURE SYSTEM Defined in the Pressure System Safety Regulations 2000 as a system containing one or more pressure vessels of rigid construction, any associated pipework and protective devices the pipework with its protective devices to which a transportable gas container is, or is intended to be, connected or a pipeline and its protective devices which contains or is liable to contain a relevant fluid, but does not include a transportable gas container. Here relevant fluid is steam any fluid or mixture of fluids which is at a pressure of >0.5 bar above atmospheric pressure, and which fluid or a mixture of fluids is a gas, or a liquid which would have a vapour pressure of >0.5 bar above atmospheric pressure when in equilibrium with its vapour at either tlie actual temperature of the liquid or 17.5°C or a gas dissolved under pressure in a solvent contained in a porous substance at ambient temperamre and which could be released from the solvent with the application of heat. 

At this point, a task analysis is performed. A "task" is defined as an activity oi performance (hat the operator sees as a unit either because of its performance character]stic.s or becau.se that activity is required as whole to achieve some part of the system goal. Only the tasks that are relevant lo the system safety are considered. A task analysis involves decomposition of each task into individual units of behavior. Unusually, this analy.sis tabulates information about each specific human aciiun. The format of such a table is not rigid - any style that allows easy retrieval ot the information can be used. The format reflects the level of detail and the type of task analysis performed. The analysis yields... 

Risk Categorization. The first step in this process is to clearly define the risk associated with the operation of this laboratory. This step includes a brief description of the operation followed by a risk assessment and a recommendation on the level of system safety required. 

The basis of safety for a chemical reaction process is the combination of measures which are relied upon to ensure safety. Defining the basis of safety for a reactor is essential as it highlights those aspects of the design and operation (hardware, protective systems and procedures) which are safety-critical. There are many factors to be considered and further advice is given in references 1 and 2. 

The Failure Mode and Effect Analysis (FMEA) is based on the systematic analysis of failure modes for each element of a system, by defining the failure mode and the consequences of this failure on the integrity of that system. It was first used in the 1960s in the field of aeronautics for the analysis of the safety of aircraft [15]. It is required by regulations in the USA and France for aircraft safety. It allows assessing the effects of each failure mode of a system s components and identifying the failure modes that may have a critical impact on the operability safety and maintenance of the system. It proceeds in four steps ... 

Every control system must comply with the concept of total safety, defined for this purpose as the complete group of standards and planned and systematized procedures necessary to guarantee the quality of the finished product... 

Let Hh denote the total material balances in ascending order Vhm nj/h) and ph, the associated probability vector. For a given total safety stock level along the pipeline r, the a-service level of the pipeline storage system is defined by Ph(,) with / determined such that r > and r < To define a safety stock level satisfying a desired... 

System dynamics steps to solve the problem (Wu J.Z. et al. 1985) is (1) to identify the problem how the coal mine safety input influence factors of coal mine production, which in turn affect coal mine safety performance (2) to determine the system boundary safety production system in coal mine (3) to determine causal graph and define the variable draw causal graph of coal mine safety production system and define the model variable (4) to establish equations, models and analyze the simulation model. 

When this term is capitalized in this book, it denotes the specific form of safety engineering developed originally by the Defense Department and its contractors for the early ICBM systems and defined by MIL-STD-882. System safety (uncapitalized) or safety engineering denotes all the approaches to engineering for safety. 

Definitions of basic terms differ greatly among industries and engineering disciplines. A set of basic definitions is used in this book (see appendix A) that reflect common usage in System Safety. An accident is defined as ... 

The term hazard has been used in different ways. For example, in aviation, a hazard is often used to denote something in the environment of the system, for example a mountain, that is in the path of the aircraft. In contrast, in System Safety, a hazard is defined as within the system being designed (or its relationship to an environmental object) and not just in its environment. For example, an aircraft flying too close to a mountain would be a hazard. 

Once the mapping is complete, a gap analysis can be performed to ensure that each system safety requirement and constraint is embedded in the organizational design and to find holes or weaknesses in the design. In this analysis, concerns surfaced, particularly about requirements not reflected in the defined ITA organizational structure. 

Within the management factor, which usually accounts for majority of industrial accidents, the most important tool is a risk assessment, which examines the hazards associated with the drying operation and on that basis safety prevention and protection measures are designed. Besides these all operating, housekeeping, and maintenance procedures as well as training systems are defined by the management based on the risk assessment. 

The practice of safety, as defined, includes all fields of endeavor for which the generic base is hazards occupational safety, occupational health, environmental affairs, product safety, transportation safety, safety of the public, health physics, system safety, fire protection engineering, et cetera. 

One example of administrative control of safety during outages is the preparation of a shutdown safety plan and operational plan for the outage. An operational plan should contain lists of systems and define when specific systems shall be in operation or in active standby to... 

A Markov system is defined as a "memory-less" system where the probability of moving from one state to another is dependent only upon the current state and not past history of getting to the state. This is the primary characteristic of a Markov model. Markov models are well suited to problems where a state naturally indicates the situation of interest. In some models (characteristic of reliability and safety models) a variable follows a sequence of states. These problems are called Markov chains. 

A safety management system is defined as ongoing activities and efforts directed to control accidental losses by monitoring critical safety elements on an ongoing basis. The monitoring includes the promotion, improvement, and auditing of the critical elements regularly. 

This means that management must know what they want and determine what work is necessary to achieve the implementation of the safety management system. Safety responsibility must be assigned and the work relationship must be clearly defined to achieve the safety objectives. The safety managanent system must have a set of standards, targets, and timelines. Expectations must be set for the number of employees to be trained and the number of inspections to be carried out, among other activities. Some objectives could be ... 

Example of a Safety System Standard Defining the Safety Committee Structure... 

The purpose of a safety management system is to assist management in developing and operating a system to prevent and control accidental loss, get managers and employees involved in safety activities, and increase the effectiveness of operations within the organization. A system also defines safety authorities, responsibilities, and accountabilities and sets standards for various aspects of safety, health, and environmental protection. 

The first step for a successful FTA is to define the objective of the FTA. The resulting scope of the FTAs will depend on the exact phrasing of the top-level event as well as the scope of the controlling System Safety Assessment (e.g. see Fig. 2.5). Careful... 

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